Field of the Invention
The present invention relates to a technique to reproduce colors and gloss of an object to be printed on printed matter.
Description of the Related Art
In the field of duplication of cultural properties or the like, the technique is known that reproduces an object, such as an oil painting, with a printer by also obtaining gloss and the form of the object, in addition to colors of the object, in order to reproduce a texture of the object in more detail.
Japanese Patent Laid-Open No. 2004-299058 has disclosed the technique to stack and form a color development layer for reproducing colors, a glossy layer for reproducing gloss, and a form layer for reproducing a form on a printing medium by using a UV curable ink jet printer.
However, with the method described in Japanese Patent Laid-Open No. 2004-299058, there is a possibility that the color of an image to be observed will change due to the influence of the glossy layer formed on the color development layer. The cause of this is explained by using FIG. 1. FIG. 1 is a schematic diagram showing an example of a section of printed matter formed on a printing medium. In an area A shown in FIG. 1, a color development layer 102 is formed on a printing medium 101 and further, a glossy layer 103 is formed on the color development layer 102. On the other hand, in an area B, the color development layer 102 is formed on the printing medium 101, but the glossy layer 103 is not formed. In the case where light from a light source enters the printed matter thus formed, the behavior of the light reflected from the surface changes from area to area. In other words, in the area A where the glossy layer is formed on the color development layer, the light to be reflected from the surface is reflected irregularly, and therefore, there is a possibility that the color that is observed in the area A is different from the color that is observed in the area B. The light that is reflected irregularly from the surface of an object as described above is called surface-scattered light. Further, there is a possibility that the behavior of the surface-scattered light changes also depending on the form (e.g., thickness) of the glossy layer that is formed on the color development layer.
Consequently, the technique of color correction that takes into consideration the influence of surface-scattered light has been proposed. Japanese Patent Laid-Open No. 2005-59592 has disclosed the technique to reduce the difference in density between the density of an image and the density of an observed image by correcting the image signal representing the density of the image to be printed by taking into consideration the influence of surface-scattered light in the roughness layer (layer that reproduces the surface roughness of the image to be printed) that is formed on the uppermost surface of the printed matter.
However, with the method described in Japanese Patent Laid-Open No. 2005-59592, the image signal is corrected in accordance with not only the form (roughness) of the surface of the image to be printed but also the density of the image, and therefore, the number of correction values increases. Consequently, there is a possibility that the color correction that takes into consideration the influence of surface-scattered light will become complicated in the method described in Japanese Patent Laid-Open No. 2005-59592.